The synthesis of selected members and analogues of the triostin and quinomycin depsipeptide antibiotics will be studied. The synthesis of analogues containing only two N-methylamino acid residues, rather than the normal four, will be carried out. The introduction of new heterocyclic chromophores in place of the quinoxaline chromophore will be accomplished. Analogues containing a sulfide rather than disulfide unit will be prepared from intact lanthionine precursors or by disulfide contraction on appropriate antibiotics. Approaches to the synthesis of the beta-methylthiolanthionine moiety common to the quinomycins will be investigated. Analogues prepared in this study will be evaluated for their binding properties to deoxynucleic acids.